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Etilefrine
Etilefrine is a cardiac stimulant used as an antihypotensive. It is a sympathomimetic amine of the 3-hydroxy-phenylethanolamine series used in treating orthostatic hypotension of neurological, cardiovascular, endocrine or metabolic origin. Intravenous infusion of this compound increases cardiac output, stroke volume, venous return and blood pressure in man and experimental animals, suggesting stimulation of both α and β adrenergic receptors. However, ''in vitro'' studies indicate that etilefrine has a much higher affinity for β1 (cardiac) than for β2 adrenoreceptors. Intravenous etilefrine increases the pulse rate, cardiac output, stroke volume, central venous pressure and mean arterial pressure of healthy individuals. Peripheral vascular resistance falls during the infusion of 1–8 mg etilefrine but begins to rise at higher dosage. Marked falls in pulse rate, cardiac output, stroke volume and peripheral bloodflow, accompanied by rises in mean arterial pressure, occu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpha-1 Adrenergic Receptor
alpha-1 (α1) adrenergic receptors are G protein-coupled receptors (GPCRs) associated with the Gq heterotrimeric G protein. α1-adrenergic receptors are subdivided into three highly homologous subtypes, i.e., α1A-, α1B-, and α1D-adrenergic receptor subtypes. There is no α1C receptor. At one time, there was a subtype known as α1C, but it was found to be identical to the previously discovered α1A receptor subtype. To avoid confusion, naming was continued with the letter D. Catecholamines like norepinephrine (noradrenaline) and epinephrine (adrenaline) signal through the α1-adrenergic receptors in the central and peripheral nervous systems. The crystal structure of the α1B-adrenergic receptor subtype has been determined in complex with the inverse agonist (+)-cyclazosin. Effects The α1-adrenergic receptor has several general functions in common with the α2-adrenergic receptor, but also has specific effects of its own. α1-receptors primarily mediate smooth muscle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Racemic Mixture
In chemistry, a racemic mixture, or racemate (), is one that has equal amounts of left- and right-handed enantiomers of a chiral molecule or salt. Racemic mixtures are rare in nature, but many compounds are produced industrially as racemates. History The first known racemic mixture was racemic acid, which Louis Pasteur found to be a mixture of the two enantiomeric isomers of tartaric acid. He manually separated the crystals of a mixture by hand, starting from an aqueous solution of the sodium ammonium salt of racemate tartaric acid. Pasteur benefited from the fact that ammonium tartrate salt that gives enantiomeric crystals with distinct crystal forms (at 77 °F). Reasoning from the macroscopic scale down to the molecular, he reckoned that the molecules had to have non-superimposable mirror images. A sample with only a single enantiomer is an ''enantiomerically pure'' or ''enantiopure'' compound. Etymology From racemic acid found in grapes; from Latin ''racemus'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Central Venous Pressure
Central venous pressure (CVP) is the blood pressure in the venae cavae, near the right atrium of the heart. CVP reflects the amount of blood returning to the heart and the ability of the heart to pump the blood back into the arterial system. CVP is often a good approximation of right atrial pressure (RAP), although the two terms are not identical, as a pressure differential can sometimes exist between the venae cavae and the right atrium. CVP and RAP can differ when arterial tone is altered. This can be graphically depicted as changes in the slope of the venous return plotted against right atrial pressure (where central venous pressure increases, but right atrial pressure stays the same; VR = CVP − RAP). CVP has been, and often still is, used as a surrogate for preload, and changes in CVP in response to infusions of intravenous fluid have been used to predict volume-responsiveness (i.e. whether more fluid will improve cardiac output). However, there is increasing evidence t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cardiac Stimulants
The heart is a muscular organ in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon dioxide to the lungs. In humans, the heart is approximately the size of a closed fist and is located between the lungs, in the middle compartment of the chest. In humans, other mammals, and birds, the heart is divided into four chambers: upper left and right atria and lower left and right ventricles. Commonly the right atrium and ventricle are referred together as the right heart and their left counterparts as the left heart. Fish, in contrast, have two chambers, an atrium and a ventricle, while most reptiles have three chambers. In a healthy heart blood flows one way through the heart due to heart valves, which prevent backflow. The heart is enclosed in a protective sac, the pericardium, which also contains a small amount of fluid. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beta-adrenergic Agonists
Adrenergic means "working on adrenaline (epinephrine) or noradrenaline (norepinephrine)" (or on their receptors). When not further qualified, it is usually used in the sense of enhancing or mimicking the effects of epinephrine and norepinephrine in the body. * Adrenergic nervous system, a part of the autonomic nervous system that uses epinephrine or norepinephrine as its neurotransmitter Regarding proteins: * Adrenergic receptor, a receptor type for epinephrine and norepinephrine; subtypes include α1, α2, β1, β2, and β3 receptors * Adrenergic transporter (norepinephrine transporter), a protein transporting norepinephrine from the synaptic cleft into nerve cells Regarding pharmaceutical drugs: * Adrenergic receptor agonist, a type of drug activating one or more subtypes of adrenergic receptors ** This includes drugs regulating blood pressure and antiasthmatic drugs. * Adrenergic receptor antagonist, a type of drug blocking one or more subtypes of adrenergic receptors ** Thi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpha-1 Adrenergic Receptor Agonists
Alpha 1 or Alpha-1 may refer to: *Alpha-1 adrenergic receptor, a G protein-coupled receptor *Alpha-1 antitrypsin, a protein ** Alpha-1 antitrypsin deficiency, a genetic disorder * Alpha-1-fetoprotein or Alpha-fetoprotein, a protein *Alpha-One, a fictional spacecraft in '' Buzz Lightyear of Star Command: The Adventure Begins'' * ''Alpha 1'' (Robert Silverberg anthology), a 1970 book See also * * * Alpha (other) *AMY1A Alpha-amylase 1 is an enzyme that in humans is encoded by the ''AMY1A'' gene In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth' ... or Alpha-1A or, an enzyme found in humans and other mammals * List of A1 genes, proteins or receptors {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propranolol
Propranolol, sold under the brand name Inderal among others, is a medication of the beta blocker class. It is used to treat high blood pressure, a number of types of irregular heart rate, thyrotoxicosis, capillary hemangiomas, performance anxiety, and essential tremors, as well to prevent migraine headaches, and to prevent further heart problems in those with angina or previous heart attacks. It can be taken by mouth or by injection into a vein. The formulation that is taken by mouth comes in short-acting and long-acting versions. Propranolol appears in the blood after 30 minutes and has a maximum effect between 60 and 90 minutes when taken by mouth. Common side effects include nausea, abdominal pain, and constipation. It should not be used in those with an already slow heart rate and most of those with heart failure. Quickly stopping the medication in those with coronary artery disease may worsen symptoms. It may worsen the symptoms of asthma. Caution is recommended in tho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peripheral Vascular Resistance
Vascular resistance is the resistance that must be overcome to push blood through the circulatory system and create flow. The resistance offered by the systemic circulation is known as the systemic vascular resistance (SVR) or may sometimes be called by the older term total peripheral resistance (TPR), while the resistance offered by the pulmonary circulation is known as the pulmonary vascular resistance (PVR). Systemic vascular resistance is used in calculations of blood pressure, blood flow, and cardiac function. Vasoconstriction (i.e., decrease in blood vessel diameter) increases SVR, whereas vasodilation (increase in diameter) decreases SVR. Units for measuring Units for measuring vascular resistance are dyn·s·cm−5, pascal seconds per cubic metre (Pa·s/m3) or, for ease of deriving it by pressure (measured in mmHg) and cardiac output (measured in L/min), it can be given in mmHg·min/L. This is numerically equivalent to hybrid resistance units (HRU), also known as Wood unit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mean Arterial Pressure
In medicine, the mean arterial pressure (MAP) is an average blood pressure in an individual during a single cardiac cycle. MAP is altered by cardiac output and systemic vascular resistance. Testing Mean arterial pressure can be measured directly or determined by using a formula. The least invasive method is the use of an blood pressure cuff which gives the values to calculate the mean pressure. A similar method is to use a oscillometric blood pressure device that works by a cuff only method where a microprocessor determines the systolic and diastolic blood pressure. Invasively, an arterial catheter with a transducer is placed and the mean pressure is determined by the subsequent waveform. Calculation While MAP can only be measured directly by invasive monitoring. The MAP can be estimated by using a formula in which the lower (diastolic) blood pressure is doubled and added to the higher (systolic) blood pressure and that composite sum then is divided by 3 to estimate MAP. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adrenoreceptors
The adrenergic receptors or adrenoceptors are a class of G protein-coupled receptors that are targets of many catecholamines like norepinephrine (noradrenaline) and epinephrine (adrenaline) produced by the body, but also many medications like beta blockers, beta-2 (β2) agonists and alpha-2 (α2) agonists, which are used to treat high blood pressure and asthma, for example. Many cells have these receptors, and the binding of a catecholamine to the receptor will generally stimulate the sympathetic nervous system (SNS). The SNS is responsible for the fight-or-flight response, which is triggered by experiences such as exercise or fear-causing situations. This response dilates pupils, increases heart rate, mobilizes energy, and diverts blood flow from non-essential organs to skeletal muscle. These effects together tend to increase physical performance momentarily. History By the turn of the 19th century, it was agreed that the stimulation of sympathetic nerves could cause diff ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cardiac Stimulant
A cardiac stimulant is a substance which acts as a stimulant of the heart – e.g., via positive chronotropic or inotropic An inotrope is an agent that alters the force or energy of muscular contractions. Negatively inotropic agents weaken the force of muscular contractions. Positively inotropic agents increase the strength of muscular contraction. The term ''inotro ... action. Examples of cardiac stimulant drugs are cocaine and methamphetamine. References External links * {{cardiovascular-system-drug-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
